R02 · complementary joint study

Cupola restored.
Nominal joint fit checked.

The cupola posts join the lower ties at the bottom datum. Two source-supported octagonal timber bands frame the open well; eight roof rafters close above it. Main hips have flat tops, with no backing bevel.

The lower cupola ring was an unsupported reconstruction and is removed. Use P0 corner close-up, Cupola connections or Inspect rafter-to-hip joints in the viewer. The exploded-view slider stays visible. Select a timber to reveal its bright, transparent sockets and notches.

Complementary shapes

Each proposed tongue and socket uses the same solid. The all-pairs check tests every permanent wood pair for positive-volume intersection, then verifies surface contact at each registered joint and confirms every member remains one connected solid.

Centered shoulder tenons, diagonal brace sockets and shallow roof bearing seats are explicit draft details. Tenon insertion of 2 in, width of one third of the member and 1 in depth shoulders are design assumptions. They are not recovered fabrication dimensions or a structural rating.

Source dimensions retained

Cupola: 7 ft 4 in outside, 6 ft 4 in inside, 41 in post-center radius, approximately 2 ft 4⅛ in outward-corner gap. Roof: radial 4:12 with 12 in radial overhang. Upper and sill bands: readable 4 × 6 callouts. Lower radial ties: 6 × 10 as previously directed by Stewart, overriding the source 6 × 8 callout.

The roof bearing offset and ring height account for timber depth. Ground height, the exact glazing-height endpoints, cupola roof timber depth, pegs and steel attachments remain unverified. No permanent member crosses the bottom opening.

Zero nominal overlap and shared contact surfaces establish mathematical fit. Load capacity, shrinkage allowances, tension restraint, machining and an executable raising sequence still require design verification.

Current geometry audit · Dimension register

Joint strength and load-path audit: central withdrawal restraint and receiver proportions require redesign. Simple integral dovetails are a candidate, not a verified strength upgrade. The horizontal half-inch plywood and eight exposed ceiling spokes are now shown separately from the pitched roof; finish-board thickness remains unresolved.